Add realtime rtc protocol support

Adds the realtime_rtc protocol path so app-server clients can negotiate WebRTC media while core keeps realtime events and tool handling. Regenerates protocol/config schemas for the new request and response shapes.

Co-authored-by: Codex <noreply@openai.com>

codex-rs/app-server-protocol/schema/json/ClientRequest.json

@@ -2815,6 +2815,47 @@
       ],
       "type": "object"
     },
+    "ThreadRealtimeStartProtocol": {
+      "description": "EXPERIMENTAL - realtime start protocol selected by the client.",
+      "oneOf": [
+        {
+          "properties": {
+            "type": {
+              "enum": [
+                "jsonRpcPcm"
+              ],
+              "title": "JsonRpcPcmThreadRealtimeStartProtocolType",
+              "type": "string"
+            }
+          },
+          "required": [
+            "type"
+          ],
+          "title": "JsonRpcPcmThreadRealtimeStartProtocol",
+          "type": "object"
+        },
+        {
+          "properties": {
+            "offerSdp": {
+              "type": "string"
+            },
+            "type": {
+              "enum": [
+                "rtc"
+              ],
+              "title": "RtcThreadRealtimeStartProtocolType",
+              "type": "string"
+            }
+          },
+          "required": [
+            "offerSdp",
+            "type"
+          ],
+          "title": "RtcThreadRealtimeStartProtocol",
+          "type": "object"
+        }
+      ]
+    },
     "ThreadResumeParams": {
       "description": "There are three ways to resume a thread: 1. By thread_id: load the thread from disk by thread_id and resume it. 2. By history: instantiate the thread from memory and resume it. 3. By path: load the thread from disk by path and resume it.\n\nThe precedence is: history > path > thread_id. If using history or path, the thread_id param will be ignored.\n\nPrefer using thread_id whenever possible.",
       "properties": {